/*****************************************************************************
*                                                                            *
*   IFFT2.SPL    Copyright (C) 1998-2011 DSP Development Corporation         *
*                               All Rights Reserved                          *
*                                                                            *
*   Author:      Randy Race                                                  *
*                                                                            *
*   Synopsis:    Performs 2D IFFT of an input array                          *
*                                                                            *
*   Revisions:   12 Mar 1998  RRR  Creation                                  *
*                13 Oct 1999  RRR  1D case                                   *
*                19 May 2000  RRR  optional lengths                          *
*                30 Jun 2009  RRR  conjugate transpose                       *
*                28 Feb 2011  RRR  removed conjugate transpose               *
*                                                                            *
*****************************************************************************/

#if @HELP_IFFT2

    IFFT2

    Purpose: Calculates the 2D IFFT of an array

    Syntax:  IFFT2(array, rowlen, collen)

              array - a multi-column series

             rowlen - optional intger, IFFT row size, defaults to
                      numrows(a)

             collen - optional integer, IFFT column size, defaults to
                      numcols(a)


    Returns: A complex array

    Example:
             ifft2(fft2({{1, 2}, {3, 4}}))

             returns the complex array {{1+0i, 2+0i},
                                        {3+0i, 4+0i}}


    Remarks:
             Since IFFT2 returns a complex result, the result can be converted
             into real form using the REAL function.

             If the input data is a series (i.e. a single column), a 1D IFFT
             is performed.


    See Also
             FFT2
             IFFT

#endif


/* 2D IFFT */
ifft2(a, rowlen, collen)
{
        if (argc < 3)
        {
                if (argc < 2)
                {
                        if (argc < 1) error("ifft2 - input array required");
                        
                        rowlen = numrows(a);
                        collen = numcols(a);
                }
                else
                {
                        collen = numcols(a);
                }
        }
        if (numcols(a) > 1)
        {
                /* amazingly simple one liner */
                return(transpose(ifft(transpose(ifft(a, rowlen)), collen)));
        }
        else
        {
                return(ifft(a, rowlen));
        }
}